1. I'm not sure what you mean by 'purple light'? Do you mean a blacklight? If so, no these are NOT the same. blue LED
moonlights are very very dim, and put out a weak spectrum that the fish don't detect. a blacklight puts out UV
light, and will not be good to run as a moonlight.
After I read the rest of your post, it sounds like you're talking about actinic03 bulbs...again, these are not the same as moonlights, and are way too bright.
moonlights can run 24/7. That's how I do mine. Since moonlights are dim, when the main lights are on in the day, you don't see any moonlighting.